This invention relates to a rechargeable pack and to the combination of the rechargeable battery pack with a hand lantern or similar device which also uses a conventional lantern battery.
Devices such as hand lanterns have been available for a long time. Most of them have been designed to accept a zinc carbon lantern battery, which is not rechargeable. Other batteries, such as alkaline types, have come to the market, but are also not rechargeable. The usefulness and the cost of using a hand lantern are adversely affected by having to replace the lantern battery, a relatively standard one of which has an average useful life of approximately four hours.
Rechargeable lighting sources, such as flashlights, have also been developed. In one such device, a rechargeable battery and the charging mechanism are sealed in the flashlight case, and a pair of blade contacts suitable for plugging into a standard wall outlet extend from the flashlight case and are covered by a snap-on cover during normal use of the flashlight. When the batteries become discharged from use of the light, the cover is removed and the entire flashlight unit is plugged into a wall outlet for recharging.
Rechargeable hand lanterns have also appeared on the market. A hand lantern is essentially a large flashlight employing a reflector of approximately three or more inches in diameter and utilizing a case larger than a standard flashlight case, the case ordinarily being adapted to receive a six-volt "lantern battery". The six-volt lantern battery is generally square in sectional shape, and has two spring terminals extending from its top face for making contact with the base of the bulb and the switch mechanism used in the hand lantern.
A first rechargeable hand lantern employs a rechargeable battery shaped similarly to a standard lantern battery, so that it fits in a standard hand lantern body. However, in place of the spring terminals found on the face of the standard lantern battery, the rechargeable battery has wire leads with a plug type end connector, and the hand lantern itself is provided with complementary plug connector with wiring providing the requisite connections to the bulb and switch mechanism. The battery is removed from the lantern body for charging, charging being accomplished by a separate charging transformer connected by a plug terminal to the battery with the charging transformer itself being plugged into a wall outlet. After the battery has been recharged, the plug connections made for recharging are separated, the battery is replaced in the lantern, and the plug connection with the lantern wiring is re-established. A disadvantage in this system is the possibility of loss or difficulty in locating the charging transformer and the loss of use of the lantern during the recharging period unless there is a second battery complete with the necessary plug connector ready for use.
A second lantern has rechargeable lead acid batteries mounted in the lantern housing together with a transformer and line cord for connecting the charging transformer to a wall outlet. When the batteries become discharged, the lantern is opened by removing the head assembly (including the reflector, lens, bulb and bulb receptacle) to gain access to the charging cord, which is plugged into a wall outlet for recharging the batteries. A disadvantage of this lantern is that it cannot be used for the period when the batteries are being recharged.
Thus, there is need for a more convenient serviceable solution to the problems of rechargeable batteries for hand lanterns or similar devices.